1. Field of the Invention
The present invention relates to an airbag, and more particularly, to an airbag device for a vehicle which may rapidly be deployed at an initial time of a deployment of an airbag cushion, exhibit appropriate shock absorbing performance when passengers are loaded, and satisfy a low risk deployment (LRD) regulation of North America to reduce an injury of children or passengers located in the vicinity of the airbag device.
2. Description of Related Art
An airbag absorbs a shock applied to passengers by appropriately expanding an airbag cushion when an accident of a vehicle occurs to reduce or prevent an injury of the passengers and therefore an expansion behavior of the airbag cushion is very critical to secure safety of the passengers.
In particular, the required expansion behavior of the airbag cushion needs to rapidly restrict the passengers by being rapidly expanded at an initial time of the deployment and appropriately emit expansion gas inside the airbag cushion when passengers are loaded to apply a load while starting to contact the airbag cushion, thereby appropriately absorbing a shock applied to the passengers.
Further, the airbag device needs to meet requirements of various regulations such as a low risk deployment (LRD) regulation of North America. In the case of the LRD regulation, the airbag cushion needs to emit the expansion gas through a vent hole at the initial time of deployment to minimize an injury of children or passengers located in the vicinity of the airbag device. Hereinafter, performance to satisfy the LRD regulation is referred to as LRD performance.
By the way, to meet the LRD performance as described above, the vent hole of the airbag cushion needs to be opened even at the initial time of the deployment of the airbag cushion to be able to partially emit the expansion gas and to rapidly expand the airbag cushion as described above, the vent hole needs to be closed at the initial time of the deployment of the airbag cushion if possible and once passengers do not start to load until the airbag cushion reaches a fully deployed state, the vent hole needs to be opened to be able to emit the expansion gas. As such, it is difficult to appropriately open or close the vent hole at an appropriate timing in response to a progress of the deployment process of the airbag cushion, a seating condition of passengers, or the like.
Meanwhile, a related art entitled “Airbag Cushion Having Variable Vent” is disclosed.
However, the above related art is also hardly to open or close the vent hole at an appropriate timing in response to the progress of the deployment process of the airbag cushion, the seating condition of the passengers, or the like.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.